Long-Term Archiving of Signed Data Using Hash Trees

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Solution Overview

Problem

Existing methods for long-term archiving of electronically signed documents are costly due to the need for frequent qualified time stamps, which lose legal validity over time as cryptography algorithms become vulnerable to improved computer power and analysis, necessitating regular re-signing with new algorithms and parameters.

Innovation Solution

A method that reduces the number of qualified time stamps by using advanced time stamps validated in predetermined intervals, combined with hash trees and cryptography, allowing for secure and cost-effective storage by replacing frequent qualified time stamps with a single daily stamp, ensuring legal validity and authenticity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If qualified electronic signatures are used to ensure legal validity of archived data, then the authenticity and legal effect are improved, but the cost increases due to frequent re-signing requirements

Engineering Contradiction:
Improvelegal validityVSAvoidcost
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by creating a hash value of the archived data and storing it together with the original data. This hash value serves as a preliminary cryptographic representation that remains valid even when the original signature expires, eliminating the need for frequent re-signing while maintaining verification capability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a cryptographic copy of the data in the form of a hash value. This hash copy is stored alongside the original data and can be used for future verification without requiring the original qualified signature, thus reducing the need for repeated costly signing operations.

Inventive Principle:
Principle #26Copying

2Reliability

If cryptography algorithms are used for signing data, then the security and forgery resistance are improved, but the validity period decreases due to advancing computer power and cryptoanalysis

Engineering Contradiction:
ImprovesecurityVSAvoidvalidity period
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent creates a hash value of the archived data and stores it together with the original data. This hash value serves as a preliminary cryptographic representation that remains valid even when the original signature expires, eliminating the need for frequent re-signing while maintaining verification capability.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If qualified time stamps are obtained frequently to maintain legal validity, then the authenticity is improved, but the productivity decreases due to time-consuming processes

Engineering Contradiction:
ImproveauthenticityVSAvoidefficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent creates a hash value of the archived data and stores it together with the original data. This hash value serves as a preliminary cryptographic representation that remains valid even when the original signature expires, eliminating the need for frequent re-signing while maintaining verification capability.

Inventive Principle:
Principle #10Preliminary action

4Adaptability or versatility

If hash values are stored separately from original data, then the storage flexibility is improved, but the verification complexity increases

Engineering Contradiction:
Improvestorage flexibilityVSAvoidverification complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the hash value storage with the original data storage by storing them together in the same archive system. This integration simplifies the verification process as both the original data and its hash representation are readily accessible together, eliminating the need for separate retrieval operations.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS8397074B2Method and computer system for long-term archiving of qualified signed data
Publication Date: 2013.03.12 ARTEC COMP

AI summary

The current invention describes a method for long term archiving of qualifiedly signed data in accordance with the current invention, which comprises the steps of hashing the data, encrypting the data through a cryptography algorithm, hashing the encrypted data, signing the hashed data with an advanced time stamp, generating a hash tree over the whole data file or the subgroups thereof and signing the hash tree(s) with a qualified time stamp. Furthermore, a computer system for conducting the method is disclosed.